E-coli also has an alternative cAMP independent catabolite repression mechanism that utilizes a protein called catabolite repressor activator (Cra). This same mechanism is also present in Gram-positive bacteria such as Bacilus subtilis, however it is called catabolite control protein A (CcpA). In this alternative pathway CcpA negatively represses other sugar operons so they are off in the presence of glucose. It works by the fact that Hpr is phosphorylated by a specific mechanism, when glucose enters through the cell membrane protein EIIC, and when Hpr is phosphoralated it can then allow CcpA to block transcription of the alternative sugar pathway operons at their respective cre sequence binding sites.